Shark Heart Research Articles

Pid-Based Bottle Shark Heart Heater Design and Development

Traditional medicines are ingredients or ingredients in the form of plant ingredients, animal ingredients, mineral ingredients, galenic preparations, or mixtures of these materials, which have been used for generations for treatment and can be applied according to the norms in force in society. Bottle shark (Centrophorus atromarginatus) has good prospects as a producer of liver oil; this fish is easy to catch and occurs in relatively large quantities in Indonesian waters. The catch rate until now is only 39% of its sustainable potential. Bottled shark liver oil contains 90% squalene, Vitamin A, and Omega, which are very useful for the human body as a supplement for heart disease and stomach ulcers and increase stamina and brain intelligence. The rapid Development of technology certainly benefits the people who use it. One example of today's use of technology is applying a technology system for the fisheries sector. This tool works automatically to monitor the processing of bottled shark livers. That way, fishermen don't have to worry about cloudy weather or things that will take longer than processing the shark liver bottle. This Bottle Shark Liver Heater uses temperatures at 31˚, 32˚, 33˚, 34˚, and 35˚. With PID (Proportional Integral Derivative) control, the quality of the Bottle Shark liver can be maintained. This tool is supported by a DS18B20 temperature sensor, Arduino uno, Relay, Ceramic Heater element, DC Fan, LCD 16X12, Power Supply, and Switch. It is hoped that the community, with this automatic system device, can make it easier to manage Bottle Shark Liver Oil.

MACRO-, MICRO-, AND ULTRA-STRUCTURAL ORGANIZATION OF TRICUSPID AND BIVALVE VALVES OF THE WHITE SHARK HEART

MACRO-, MICRO-, AND ULTRA-STRUCTURAL ORGANIZATION OF TRICUSPID AND BIVALVE VALVES OF THE WHITE SHARK HEART

The shark heart crowned

![Graphic][1] The heart works tirelessly to pump blood around the body. But, ironically, heart muscle itself is one of the tissues most reliant on an uninterrupted oxygen supply. Conventionally, there are two routes via which oxygen may reach the heart: a dedicated coronary supply or the

Characterization of the heart transcriptome of the white shark (Carcharodon carcharias)

BackgroundThe white shark (Carcharodon carcharias) is a globally distributed, apex predator possessing physical, physiological, and behavioral traits that have garnered it significant public attention. In addition to interest in the genetic basis of its form and function, as a representative of the oldest extant jawed vertebrate lineage, white sharks are also of conservation concern due to their small population size and threat from overfishing. Despite this, surprisingly little is known about the biology of white sharks, and genomic resources are unavailable. To address this deficit, we combined Roche-454 and Illumina sequencing technologies to characterize the first transciptome of any tissue for this species.ResultsFrom white shark heart cDNA we generated 665,399 Roche 454 reads (median length 387-bp) that were assembled into 141,626 contigs (mean length 503-bp). We also generated 78,566,588 Illumina reads, which we aligned to the 454 contigs producing 105,014 454/Illumina consensus sequences. To these, we added 3,432 non-singleton 454 contigs. By comparing these sequences to the UniProtKB/Swiss-Prot database we were able to annotate 21,019 translated open reading frames (ORFs) of ≥ 20 amino acids. Of these, 19,277 were additionally assigned Gene Ontology (GO) functional annotations. While acknowledging the limitations of our single tissue transcriptome, Fisher tests showed the white shark transcriptome to be significantly enriched for numerous metabolic GO terms compared to the zebra fish and human transcriptomes, with white shark showing more similarity to human than to zebra fish (i.e. fewer terms were significantly different). We also compared the transcriptome to other available elasmobranch sequences, for signatures of positive selection and identified several genes of putative adaptive significance on the white shark lineage. The white shark transcriptome also contained 8,404 microsatellites (dinucleotide, trinucleotide, or tetranucleotide motifs ≥ five perfect repeats). Detailed characterization of these microsatellites showed that ORFs with trinucleotide repeats, were significantly enriched for transcription regulatory roles and that trinucleotide frequency within ORFs was lower than for a wide range of taxonomic groups including other vertebrates.ConclusionThe white shark heart transcriptome represents a valuable resource for future elasmobranch functional and comparative genomic studies, as well as for population and other biological studies vital for effective conservation of this globally vulnerable species.

β-Adrenergic regulation of a novel isoform of NCX: sequence and expression of shark heart NCX in human kidney cells

The function, regulation, and molecular structure of the cardiac Na(+)/Ca(2+) exchangers (NCXs) vary significantly among vertebrates. We previously reported that beta-adrenergic suppression of amphibian cardiac NCX1.1 is associated with specific molecular motifs. Here we investigated the bimodal, cAMP-dependent regulation of spiny dogfish shark (Squalus acanthias) cardiac NCX, exploring the effects of molecular structure, host cell environment, and ionic milieu. The shark cardiac NCX sequence (GenBank accession no. DQ 068478) revealed two novel proline/alanine-rich amino acid insertions. Wild-type and mutant shark NCXs were cloned and expressed in mammalian cells (HEK-293 and FlpIn-293), where their activities were measured as Ni(2+)-sensitive Ca(2+) fluxes (fluo 4) and membrane (Na(+)/Ca(2+) exchange) currents evoked by changes in extracellular Na(+) concentration and/or membrane potential. Regardless of Ca(2+) buffering, beta-adrenergic stimulation of cloned wild-type shark NCX consistently produced bimodal regulation (defined as differential regulation of Ca(2+)-efflux and -influx pathways), with suppression of the Ca(2+)-influx mode and either no change or enhancement of the Ca(2+)-efflux mode, closely resembling results from parallel experiments with native shark cardiomyocytes. In contrast, mutant shark NCX, with deletion of the novel region 2 insertion, produced equal suppression of the inward and outward currents and Ca(2+) fluxes, thereby abolishing the bimodal nature of the regulation. Control experiments with nontransfected and dog cardiac NCX-expressing cells showed no cAMP regulation. We conclude that bimodal beta-adrenergic regulation is retained in cloned shark NCX and is dependent on the shark's unique molecular motifs.

β-adrenergic Regulation of a Novel Isoform of NCX: Sequence & Expression of Shark Heart NCX in Human Kidney Cells

Overexpression of the Na+/Ca2+ exchanger (NCX) in mammals is associated with arrhythmias in cardiac hypertrophy and failure. The function and regulation of NCX genes varies significantly among vertebrates likely reflecting differences in molecular structure. We have previously reported that β-adrenergic suppression of the Ca2+-efflux and -influx modes of amphibian cardiac NCX1.1 is associated with specific molecular motifs. In contrast, cardiac NCX of shark (Squalus acanthias) shows ‘bimodal’ adrenergic regulation with preferential suppression of the Ca2+-influx mode (Woo and Morad, PNAS 98:2023, 2001); and its sequence (DQ 068478) reveals two novel proline/alanine-rich AA-insertions.

Bimodal regulation of Na(+)--Ca(2+) exchanger by beta-adrenergic signaling pathway in shark ventricular myocytes.

In shark heart, the Na(+)--Ca(2+) exchanger serves as a major pathway for both Ca(2+) influx and efflux, as there is only rudimentary sarcoplasmic reticulum in these hearts. The modulation of the exchanger by a beta-adrenergic agonist in whole-cell clamped ventricular myocytes was compared with that of the Na(+)--Ca(2+) exchanger blocker KB-R7943. Application of 5 microM isoproterenol and 10 microM KB-R7943 suppressed both the inward and the outward Na(+)--Ca(2+) exchanger current (I(Na--Ca)). The isoproterenol effect was mimicked by 10 microM forskolin. Isoproterenol and forskolin shifted the reversal potential (E(rev)) of I(Na--Ca) by approximately -23 mV and -30 mV, respectively. An equivalent suppression of outward I(Na--Ca) by KB-R7943 to that by isoproterenol produced a significantly smaller shift in E(rev) of about --4 mV. The ratio of inward to outward exchanger currents was also significantly larger in isoproterenol- than in control- and KB-R7943-treated myocytes. Our data suggest that the larger ratio of inward to outward exchanger currents as well as the larger shift in E(rev) with isoproterenol results from the enhanced efficacy of Ca(2+) efflux via the exchanger. The protein kinase A-mediated bimodal regulation of the exchanger in parallel with phosphorylation of the Ca(2+) channel and enhancement of its current may have evolved to satisfy the evolutionary needs for accelerated contraction and relaxation in hearts of animals with vestigial sarcoplasmic Ca(2+) release stores.

Bimodal regulation of Na+-Ca2+ exchanger by beta -adrenergic signaling pathway in shark ventricular myocytes

In shark heart, the Na(+)--Ca(2+) exchanger serves as a major pathway for both Ca(2+) influx and efflux, as there is only rudimentary sarcoplasmic reticulum in these hearts. The modulation of the exchanger by a beta-adrenergic agonist in whole-cell clamped ventricular myocytes was compared with that of the Na(+)--Ca(2+) exchanger blocker KB-R7943. Application of 5 microM isoproterenol and 10 microM KB-R7943 suppressed both the inward and the outward Na(+)--Ca(2+) exchanger current (I(Na--Ca)). The isoproterenol effect was mimicked by 10 microM forskolin. Isoproterenol and forskolin shifted the reversal potential (E(rev)) of I(Na--Ca) by approximately -23 mV and -30 mV, respectively. An equivalent suppression of outward I(Na--Ca) by KB-R7943 to that by isoproterenol produced a significantly smaller shift in E(rev) of about --4 mV. The ratio of inward to outward exchanger currents was also significantly larger in isoproterenol- than in control- and KB-R7943-treated myocytes. Our data suggest that the larger ratio of inward to outward exchanger currents as well as the larger shift in E(rev) with isoproterenol results from the enhanced efficacy of Ca(2+) efflux via the exchanger. The protein kinase A-mediated bimodal regulation of the exchanger in parallel with phosphorylation of the Ca(2+) channel and enhancement of its current may have evolved to satisfy the evolutionary needs for accelerated contraction and relaxation in hearts of animals with vestigial sarcoplasmic Ca(2+) release stores.

Novel cardiac protective effects of urea: from shark to rat.

1. This study was carried out to investigate novel cardioprotective effects of urea and the underlying mechanisms. The cardiac functions under oxidative stress were evaluated using Langendorff perfused isolated heart. 2. Isolated dogfish shark hearts tolerated the oxidative stress generated by electrolysis (10 mA, 1 min) of the perfusion solution (n=4), and also showed normal cardiac functions during post-ischaemia reperfusion (n=4). The high concentration of urea (350 mM) in the heart perfusate was indispensable for maintaining the normal cardiac functions of the shark heart. 3. Urea at 3 - 300 mM (n=4 for each group) protected the isolated rat heart against both electrolysis-induced heart damage and post-ischaemia reperfusion-induced cardiac injury. 4. A concentration-dependent scavenging effect of urea (3 - 300 mM, n=4 for each group) against electrolysis-induced reactive oxygen species was also demonstrated in vitro. 5. Urea derivatives as hydroxyurea, dimethylurea, and thiourea had antioxidant cardioprotective effect against the electrolysis-induced cardiac dysfunction of rat heart, but were not as effective as urea in suppressing the post-ischaemia reperfusion injury. 6. Our results suggest that urea and its derivatives are potential antioxidant cardioprotective agents against oxidative stress-induced myocardium damage including the post-ischaemia reperfusion-induced injury.

TOXIC EFFECTS OF CADMIUM AND COPPER ON THE ISOLATED HEART OF DOGFISH SHARK, SQUALUS ACANTHIAS

The adverse effects of heavy metal ions on the heart functions of lower vertebrates are largely unknown. In the present study, the effects of Cd2+, Cu2+, and Cu+ on the cardiac functions of the heart isolated from dogfish shark, Squalus acanthias, including the epicardial electrocardiogram, ventricular developed pressure (VDP), and heart beating rate, were studied. Cadmium (10 to 100 muM) significantly decreased VDP of the isolated shark hearts in a reversible manner. However, heart beating rate was not affected by cadmium. Cadmium also induced a transient modification of the amplitude and the form of the QRS complex. Cupric ion transiently increased VDP in a concentration-dependent manner, whereas cuprous ion (1 to 100 muM) did not markedly alter the cardiac functions of shark. Cupric or cuprous ions did not change heart beating rate and electrocardiogram at concentrations of 10 to 100 muM. Our results, for the first time, demonstrated the effects of cadmium on shark heart and indicated that the cardiac effects of copper are valence dependent. An elucidation of heavy metal effects on fish cardiac functions will help to understand the complex toxicological properties of heavy metals in different species and tissues, and will provide information for management of pollution control and marine resource protection.

Pugnose eels, Simenchelys parasiticus (Synaphobranchidae) from the heart of a shortfin mako, Isurus oxyrinchus (Lamnidae)

A 395 kg shortfin mako, Isurus oxyrinchus (Lamnidae) landed at Montauk, New York in June of 1992 was found to contain two dead, but otherwise healthy appearing pugnose eels, Simenchelys parasiticus (Synaphobranchidae) within the lumen of its heart. The path along which the eels made their way into the shark's heart was not found. Histological examination of the shark's heart revealed the presence of medial hyperplasia and hypertrophy of small arterioles, multifocal arteriosclerosis, and relatively high numbers of capillaries per unit area. These phenomena were not observed in similar sections taken from hearts of six uninfected mako sharks. The stomachs of both eels were filled with blood, suggesting that they had been within the shark at least long enough to feed. Consideration of this new record along with the literature supports a trophic designation of facultative endoparasite for the species Simenchelys parasiticus.

The unusual adrenergic-like excitatory action of acetylcholine on the ventricular cardiac muscle of the horned shark, Heterodontus portusjacksoni.

The atypical excitatory effect of acetylcholine on cardiac ventricular muscle was investigated in the horned shark, Heterodontus portusjacksoni. Electrically paced ventricular strips produced a massive 391.45% (+/-26.39%) increase in basal force of contraction in response to exogenously applied acetylcholine. The response was similar in nature to that produced by applied adrenaline, which caused a 382.52% (+/-72.47%) increase. The response to acetylcholine was blocked by the muscarinic cholinoceptor antagonist atropine and the competitive beta-adrenoceptor antagonist propranolol and was reduced by bretylium, an agent known to inhibit the release of catecholamines from adrenergic nerves. These findings strongly suggest that acetylcholine mediates a localised release of a catecholamine via muscarinic cholinoceptors in shark heart. A cholinergically controlled catecholamine store has been proposed (cholinergic-adreno complex), implying that elasmobranchs may be capable of finer control of cardiac output than has previously been suspected. This complex may represent a transitional adrenergic state between humoral and neuronal regulation. The spontaneously beating atrium showed no evidence of such an excitatory response to applied acetylcholine but produced an atropine-sensitive slowing, a response typical of other vertebrates.

C-type natriuretic peptides are potent dilators of shark vascular smooth muscle.

Previous studies of the effects of C-type natriuretic peptides (CNP) in intact mammals have demonstrated limited hypotensive responses, in contrast to other natriuretic peptides. Our previous studies, on isolated vascular smooth muscle (VSM) from various fish species, utilizing either mammalian or non-homologous fish atrial natriuretic peptides (ANP), have demonstrated vasodilation with a relatively high sensitivity (EC50 approximately 5 nM). The recent sequencing of a C-type natriuretic peptide from the heart of the dogfish shark, Squalus acanthias, has enabled us to compare the efficacy of this peptide on aortic VSM from that species with two other CNPs (from killifish and pig), as well as rat ANP. The EC50 of dilation for sCNP, as well as kCNP and pCNP, was 0.5 nM, over 15 times lower than the EC50 of the response to rANP. These data suggest that CNP is released from the dogfish shark heart and is a circulating hormone with potent vasodilatory effects, in sharp contrast to the apparent role of CNP predominantly as a brain neuropeptide in mammals.

Identification of C-type natriuretic peptide in heart of spiny dogfish shark (Squalus acanthias)

An unidentified atrial natriuretic peptide (ANP)-like substance is the principal hormone regulating NaCl secretion in the shark rectal gland, an epithelial model tissue for hormone-sensitive secondary active chloride transport. Antibodies to mammalian ANP do not recognize the prohormone of marine species. The polymerase chain reaction (PCR) was used to isolate a partial cDNA encoding the shark heart natriuretic peptide. Using this partial sequence as a probe, the full-length clone [882 base pairs (bp)] was obtained from a shark heart cDNA library. Amino acids 119-135 are similar to the recently identified peptide sequences of porcine C-type natriuretic peptide (CNP) and killifish brain natriuretic peptide isolated from the brain of these species. Mature shark heart CNP terminates at the second cysteine residue and lacks a COOH-terminal extension, in contrast to cardiac ANP-like peptides of all other species. The primary amino acid sequence of the shark heart prepro-CNP is distinctly different from all other cardiac natriuretic peptides. Amplification of genomic DNA spanning the coding region produced a 1.5-kb product, indicating the presence of at least one intron. Sequencing confirmed the presence of two exons of 90 and 315 bp, separated by a 1.1-kb intron. This is the first report of a cDNA encoding in nonneuronal tissue. Elasmobranch CNP may represent a primordial form of ANP-like peptides that evolved as an adaptation to environmental osmoregulatory stress.

Effects of osmolality and solutes on performance of shark heart mitochondria

AbstractDogfish shark heart mitochondria isolated from Squalus acanthias were exposed to increasing concentrations of mannitol/sucrose, trimethylamine oxide (TMAO), betaine, and urea. For all but urea, respiratory control ratios (RCR) and rates of oxygen uptake (V̇O2) in the presence of malate/glutamate were low in basal medium (220 mOsm), increased with solute concerntration to about 420–870 mOsm, and declined in the highest concentrations (1,150 mOsm). Increasing urea concentration up to about 1,150 mOsm had relatively little effect on RCR or V̇O2. The results were not changed significantly by prolonged incubation in these media or by the addition of 0.3 M urea to either mannitol/sucrose or TMAO media. We conclude that, like mannitol/sucrose, betaine, and probably TMAO permeate shark heart mitochondria slowly or not at all, but that urea readily permeates the mitochondria and is thus osmotically inactive. The highest V̇O2 values were obtained in media at 580 mOsm, hypoosmotic to shark blood (897 mOsm) and to local seawater (879 mOsm) but approximately isoosmotic to blood without the osmotic contribution of the permeant urea. We conclude that V̇O2 is superior to RCR as a comparative measure of mitochondrial activity.

Atrial natriuretic peptide stimulates salt secretion by shark rectal gland by releasing VIP.

Salt secretion by the isolated perfused rectal gland of the spiny dogfish shark, Squalus acanthias, is stimulated by synthetic rat atrial natriuretic peptide (ANP II) as well as extracts of shark heart, but not by 8-bromo-cyclic guanosine 5'-monophosphate. Cardiac peptides have no effect on isolated rectal gland cells or perfused tubules, suggesting that stimulation requires an intact gland. The stimulation of secretion by ANP II is eliminated by maneuvers that block neurotransmitter release. These include: perfusion with procaine (10(-2) M), perfusion with high Mg2+ (9.5 mM) and low Ca2+ (0.5 mM) concentrations, and addition to the perfusate of the calcium channel blockers nifedipine (10(-6)M), diltiazem (5 X 10(-5)M), or verapamil (10(-4)M). Cardiac peptides stimulate the release of vasoactive intestinal peptide (VIP), known to be present in rectal gland nerves, into the venous effluent or perfused glands in parallel with their stimulation of salt secretion, but the release of VIP induced by ANP II is prevented by perfusion with procaine. Cardiac peptides thus appear to regulate rectal gland secretion by releasing VIP from neural stores within the gland. It is possible that other physiological effects of these hormones might be explained by an action to enhance local release of neurotransmitters.

Atriopeptin stimulation of rectal gland function in Squalus acanthias.

The rectal gland of the shark plays a significant role in the homeostasis of extracellular volume. Regulation of rectal gland function is under hormonal control, but the precise identity of the humoral mediator is unknown. Atriopeptin stimulates rectal gland chloride secretion in vivo. This stimulation of epithelial transport is accompanied by systemic and local hemodynamic effects. Atriopeptin also stimulates chloride secretion by the in vitro perfused rectal gland, an effect that is not accompanied by hemodynamic changes. Extracts of shark heart, but not muscle, brain, kidney, or intestine, contain a heat-stable trypsin-sensitive substance capable of in vitro stimulation of rectal gland chloride secretion. Electron micrographic analysis reveals multiple neurosecretory-like granules in atrial cardiocytes that are only rarely seen in ventricular cardiocytes. By using the in vitro perfused gland as a biologic assay, serum obtained after extracellular volume expansion reveals the presence of a rectal gland stimulatory factor that is not present in serum before expansion. These results are consistent with the hypothesis that atriopeptin is present in shark cardiocytes and is released during volume expansion. The atriopeptin stimulates rectal gland chloride secretion, providing a negative feedback mechanism for the regulation of extracellular volume.

Electron transfer in monomeric forms of beef and shark heart cytochrome c oxidase

Beef heart cytochrome c oxidase is dimeric in reconstituted membranes and in nonionic detergents at physiological pH [Henderson, R., Capaldi, R. A., & Leigh, J. (1977) J. Mol. Biol. 112, 631; Robinson, N.C., & Capaldi, R. A. (1977) Biochemistry 16, 375], raising the possibility that this aggregation state is a prerequisite for enzymatic activity. A procedure for dissociating the enzyme into monomers is presented. This involves treating the protein with high concentrations of Triton X-100 at pH 8.5. The electron transfer activity of the monomer is comparable to that of the dimer under identical assay conditions. The beef heart cytochrome c oxidase monomer was found to be heterogeneous in hydrodynamic studies, probably due to dissociation of associated polypeptides, including subunit III. Monomer molecular weights in the range 129 000-160 000 were obtained. Previous studies have indicated that shark heart cytochrome c oxidase is monomeric under physiological conditions. Sedimentation equilibrium studies reported here confirm this. The elasmobranch enzyme, with a similar polypeptide composition to that of beef enzyme, was determined to have a molecular weight of 158 000.